Do this:
Call ##PST
Go to Modem Settings
Go to Slot Cycle
Change from 2 to 1
When you have made the change, press the Menu button and save changes. (Skipping this step won't save changes)
Your phone should restart
*If it asks for a password, which it should, it is six zeros. (000000)
** Changing the slot cycle should, theoretically, lower battery life by a bit. I've done it for two months now and haven't noticed a thing. It pings the cell tower more often and should use more battery, but I haven't noticed it. If having it at "1" is still too slow, go to "0" which is actually what I'm at. It should ping even faster.
Also, try calling *228. Do the first option. Phone will shut down, reset, and when it's back up again, call again and do option "2." That may fix somethings as well.
I suggest you do both methods.